D-cycloserine helps patients learn how to conquer their fears

Mar 13 2006

Researchers from the Center for Anxiety and Related Disorders at Boston University have found that adding D-cycloserine (DCS) - a drug used to treat tuberculosis but that has also been shown to stimulate learning - to therapy programs helps people with Social Anxiety Disorder (SAD) learn how to overcome fears of social situations, such as public speaking.

The fear of public speaking is the most common among individuals with SAD, as well as in the general population. The results of the study are published in the March issue of the Archives of General Psychiatry.

Despite advances in the treatment of SAD with anti-anxiety drugs and exposure therapy, a process where the person is exposed to feared situations or objects, many patients remain symptomatic. The goal of the research was to determine if adding DCS improves the outcomes of exposure therapy for SAD.

In this double-blind, placebo-controlled study, 27 patients were randomized to receive 50 mg of D-cycloserine or placebo one hour before each of four exposure therapy sessions, conducted as part of an overall five-session treatment plan.

During the sessions, participants were required to give speeches in front of other group members or a video camera and then listen to feedback from their peers. Social anxiety symptoms were assessed by patient self-reports and clinicians blind to the randomization before treatment, after treatment, and one month following the final session. Patients who received exposure therapy plus the active drug reported significantly less anxiety compared with the placebo group.

"The results of this study offer encouraging preliminary support for the select use of DCS to help people with social anxieties learn more from therapy and achieve strong gains through relatively limited treatment," said Michael Otto, a clinical psychology professor and one of the study co-authors. "We hope to confirm these findings with additional larger studies."

The new data provide more evidence that D-cycloserine enhances the efficacy of exposure therapy in people with phobias. An earlier study conducted at Emory University demonstrated similar results in individuals with acrophobia, the fear of heights. According to Stefan Hofmann, associate professor of clinical psychology and lead investigator of the BU study, his team's research offers a number of complementary features: it represents the use of DCS in a common anxiety disorder known for its marked distress and disabling effects; it examines treatment outcomes for a condition that has been the target of large-scale combination treatment trials, with little advantage shown for the addition of drugs over behavior therapy alone; it utilizes a longer course of therapy; and, it utilizes clinicians from several sites and both individual- and group-treatment formats that are consistent with the ways in which behavior therapy is provided in clinical settings.

"Studies like this may usher in a new strategy for combining medications and cognitive-behavior therapy," suggests Dr. Otto. "Instead of simply combining medications and therapy that are each designed to reduce anxiety and avoidance, the use of DCS is directed toward making the therapeutic learning in cognitive-behavior therapy stronger. Medication use is limited to only a few doses, taken before therapy sessions."

Researchers from the anxiety clinics at Massachusetts General Hospital and Southern Methodist University also participated in the study.

Social Anxiety Disorder is the third most common psychiatric condition in the U.S. behind depression and alcohol abuse. If left untreated, the disorder typically follows a chronic, unremitting course that can lead to substantial impairments in vocational and social functioning.